The disposition of leaves, small twigs, grasses and the like is a significant problem, particularly when considered in connection with the commercial harvesting of nut crops where valuable crop material may lie on the ground mixed in with the unwanted vegetable matter. It is desired to pick up the debris and crop together and to pulverize, comminute or shred only the debris, which debris then may be separated from the crop and easily transported, in view of the resulting decrease in its bulk.
Prior developments in this field will be generally illustrated by reference to the following patents:
______________________________________ Patent No. Patentee Issue Date ______________________________________ 3,049,857 Shaw 08/21/62 3,712,353 Ferry 01/23/73 Re.29,139 Messner 02/22/77 3,940,827 Greco 03/02/76 2,809,389 Collins et al. 10/15/57 4,043,100 Aumann et al. 08/23/77 2,658,318 Miller 11/10/53 2,538,643 Gregory 01/16/51 3,184,777 Norden 05/25/65 ______________________________________
The patent to E. S. Ferry, U.S. Pat. No. 3,712,353 shows a suction chute (rather than a hose) leading to a chamber in which a single blade spins on a rotating shaft. A fan behind the blade sucks leaves past the blade and discharges the shreddings. J. D. Shaw, U.S. Pat. No. 3,049,857 teaches a similar machine except that the fan precedes the single blade.
U.S. Pat. Nos. Re. 29,l39 and 3,940,827 teach vacuums attached to lawn mowers for disintegrating leaves and the like.
U.S. Pat. Nos. 2,809,389, 4,043,100, 2,658,318 and 2,538,643 show vacuum shredders of various configurations.
The rest of the patents are representative of what is in the art.
A disadvantage of prior devices is that they utilize blades which are rigidly fixed to spinning shafts. Such blades are easily dulled or broken by rocks or other foreign objects. Furthermore, they are difficult to repair and expensive to replace.